Syamir Alihan Showkat Ali
Thumbnail Image
Preferred name
Syamir Alihan Showkat Ali
Official Name
Syamir Alihan, Showkat Ali
Alternative Name
Alihan Showkat Ali, Syamir
Showkat Ali, Syamir A.
Ali, Syamir Alihan Showkat
Showkat Ali, S.A
Showkat Ali, Syainir Alihan
Main Affiliation
Scopus Author ID
57190746528

Research Output

Filters

2 1
12
Reset filters

Settings
Now showing 1 - 10 of 12
Thumbnail Image
Publication

Aeroacoustic performance of high-lift airfoil with serrated slat cusp

2020-01-01 , Jawahar H.K. , Syamir Alihan Showkat Ali , Azarpeyvand M. , da Silva C.R.I.

Experimental measurements to assess the aeroacoustic capabilities of 30P30N airfoil fitted with two different types of serrated slat cusps were carried out at the aeroacoustic wind tunnel at the University of Bristol. The results from the simultaneous surface pressure measurement within and close to the slat cove region and far-field noise measurements above the slat trailing edge are presented to gain a deeper understanding of the noise generation mechanism of the slat and other presented configurations. The far-field noise measurement results showed that significant noise reduction at the vortex shedding frequency can be achieved by the use of serration-2 and No-Cusp configuration. The coherence results for all the frequencies are almost zero for the No-Cusp configuration and the coherence was notably reduced for the Serration-2 configuration. Further higher order statistical and spectral analysis showed that even the serration-1 with small serrations reduces the energy within the norrowband peaks to some level.

View
Thumbnail Image
Publication

Turbulent flow interaction with a circular cylinder

2020-01-01 , Maryami R. , Syamir Alihan Showkat Ali , Azarpeyvand M. , Afshari A.

This paper presents a comprehensive experimental study on the unsteady pressure exerted on the surface of a round cylinder in smooth and turbulent flows. A highly instrumented cylinder with several static pressure taps and dynamic pressure transducers at different spanwise and peripheral locations was used, enabling extensive dynamic surface pressure, coherence, and turbulence length-scale analysis. The effects of the free-stream turbulence and turbulent length scale are investigated by placing the turbulent-generating grids within the wind tunnel duct. For both the laminar and turbulent incident flows, the surface pressure results show the emergence of the fundamental, first and second harmonics at most peripheral angles, while at the cylinder base, the surface pressure spectra are dominated by the first harmonic. It has also been observed that an increase in the level of the turbulence intensity results in an increase in the energy level of unsteady pressure acting on the cylinder. An increase in the length scale of the incoming flow structures is shown to result in an increase in the energy level of the tonal frequencies and the broadband content of the surface pressure spectra. The spanwise coherence results have also shown that an increase in the length scale of the flow structures increases the spanwise correlation length of the flow structures at the vortex shedding frequency at the stagnation point, while at the cylinder base, the spanwise correlation length decreases at the vortex shedding frequency.

View
Thumbnail Image
Publication

Design and Mechanical Analysis on a Compact Bicycle Loader for a Small Cubic Centimeter Motorcycle

2021-01-01 , Mohd Sabri Hussin , Sanusi Hamat , Syamir Alihan Showkat Ali

This paper presents the finite element and fluid-flow analysis on the behavior of a new compact bicycle loader design used for a small cubic centimeter motorcycle. The bicycle loader in the current market comes with various sizes and design which mostly applicable to the large-scale vehicles, namely car and motorcycle with higher cubic centimeter engines. The study aims to design a new compact bicycle loader specifically for small cubic centimeter motorcycles with greater loading capability and security. The finite element analysis was performed using the ABAQUS and ANSYS software to better understand the static and dynamic response of the bicycle loader relating to static and fatigue strengths with specific loads. The fluid-flow to structure analysis has also been carried out using the XFlow Computational Fluid Dynamic software to demonstrate the flow behavior and effect on the bicycle loader with different motorcycle speed. The fatigue analysis was carried out to analyze the structural performance of the bicycle loader. Factors like fatigue life, safety factor, biaxiality indication and fatigue response are plotted for the bicycle loader and the fatigue performance is predicted using the data obtained. The results of the stress distribution show that the maximum von-Mises stress obtained from is about 31.7 MPa, well within the yield strength if the mild steel material. The results show that the highest stress distribution occurs at the mounting part of the bicycle loader, with equivalent stress of 50.29 MPa. The results show that there are no permanent deformations occurred in the bicycle loader during the fatigue test and fulfils the minimum safety requirements needed. The fluid flow analysis show that a strong recirculation region occurs at the front of the motorcycle, bicycle headset and suspension fork and downstream of the bicycle tires, however, no obvious flow disturbance is observed in the vicinity of the bicycle loader.

View
Thumbnail Image
Publication

Control of flows around bluff bodies mediated by porous materials

2020-06-01 , Sadeghipour, Sakineh , Syamir Alihan Showkat Ali , Liu, Xiao , Azarpeyvand, Mahdi , Thorpe, Graham R.

There is evidence that the application of porous media to the surfaces of bluff bodies immersed in turbulent fluid flows has a profound effect on the associated aerodynamic phenomena. This idea is explored by performing a series of experiments on cylinders that have circular, square and rectangular cross sections. The flow fields were established around circular cylinders that had been encased in porous media, and which retained the same dimensions of the bare cylinder. The square and rectangular bluff bodies were modified so that their upstream and downstream halves consisted of solid and porous materials respectively. It is found that the porous media applied to the circular cylinder had the most effect on the wake, and the largest effect was observed in the wake generated by the most permeable material. The principal effect of the porous media was to cause the eyes of the recirculation region to be located further downstream. The effect of the permeability is increasingly diminished in the square and rectangular geometries. The presence of the porous media also had a significant effect on the Reynolds stresses. The effect of the porous media applied is to damp the normal stresses further downstream of the bluff bodies.

View
Thumbnail Image
Publication

Ergonomic intervention study among woodball players

2020 , M. F. Abd Razak , A. H. Mazelan , Syamir Alihan Showkat Ali , Suhizaz Sudin

This paper proposed a feasibility study on the ergonomics intervention among the Woodball athletes. The objectives of this study are to identify the ergonomics risk factors that may cause harm to Woodball athlete by using the Initial Ergonomic Risk Assessment (ERA) and the Advanced ERA method. The ergonomic assessment of an athlete was focussed on the three different woodball exercises, namely the tee-off comprising of short tee-off, medium tee-off and long tee-off. The advanced ergonomic risk assessments were performed on the upper body part of an athlete such as the neck, shoulder, upper arm, hand or wrist and upper back by using the RULA employee assessment worksheet. Based on the findings and assessment done, the proper body posture is then proposed through the observation from the results of the initial and advanced ERA. A simulation using the Human Digital Modelling (HDM) was also performed to better analyse the ergonomic aspect of the selective body postures. The results of the simulation were then compared to the results of the RULA assessment. The improvised results from the RULA analysis were found to be able to reduce the ergonomics risk of the current and improvised posture. The improvised posture will be useful for future studies in order to obtain a more ideal body posture for the Woodball players.

View
No Thumbnail Available
Publication

Near-field pressure and wake velocity coherence of a circular cylinder

2023 , Reza Maryami , Syamir Alihan Showkat Ali

Aerodynamic noise and unsteady loads resulting from the vortex shedding of a circular cylinder pose significant challenges in engineering applications. Understanding these challenges is closely related to pressure fluctuations on the cylinder surface. This experimental study conducted simultaneous measurements of surface pressure and velocity fluctuations within the subcritical Reynolds number range ( 14.7 × 10 3 ≤ R e ≤ 30 × 10 3 ) to investigate the influence of vortex shedding on near-field pressure. The experiments utilized a highly instrumented cylinder with mini-pressure transducers. The results revealed that surface pressure fluctuations exhibit maximum energy content near the cylinder's shoulders at the fundamental vortex shedding frequency (f0), aligning with pronounced lift fluctuations. The analysis of pressure-velocity coherence indicated that the most energetic flow structures resulting from vortex shedding significantly contribute to generating surface pressure fluctuations at the f0-peak frequency, extending over a considerable distance from the near- to far-wake regions. Additionally, the pressure fluctuations responsible for drag fluctuations are predominantly imposed at the base of the cylinder, primarily at the second harmonic ( 2 f 0 ), arising from flow structures shed at the end of the vortex formation region. Wavelet analysis provided insights into the temporal characteristics of surface pressure fluctuations, revealing amplitude modulation over time with multiple repetitive patches around the f0-peak frequency and close to the cylinder's shoulders, where the highest energy level predominates due to vortex shedding.

View
Thumbnail Image
Publication

Effects on Ply Orientation of Kevlar/Epoxy for Ballistic Impact in Bulletproof Vest Using Non-linear Finite Element Analysis

2021-01-01 , Sanusi Hamat , Mohd Sabri Hussin , Syamir Alihan Showkat Ali , Maliki Ibrahim

The bulletproof vest is vital equipment to stop bullets from penetrating the body. The vest comes with a ballistic panel that can absorb the energy from the ballistic impact. Due to excellent impact resistance and high strength-to-weight ratio, Kevlar fibers composites are widely used for designing a ballistic panel in bulletproof vest body armor to avoid penetration. In this study, the research aims to investigate the ballistic impact behavior on a ballistic panel of Kevlar/Epoxy by using different fibers ply orientation to increase the ballistic impact performance. A finite element analysis using non-linear dynamic simulation was developed in commercial software Abaqus/Explicit to analyze the performance of impact characteristics in penetration depth, damage criteria, and energy-absorbing capacity. The simulation results show that the fibers ply orientation sequence of [0/90/0/90]2sym with 4 mm panel thickness has produced the highest energy absorption of 1523.7 J with least depth penetration of 2.12 mm for the 9 mm bullet traveling at 358 m/s and produce a lowest Hashin’s damage criteria with the value of 0.40. The finding shows that the ply orientation of Kevlar/Epoxy composite ballistic panel has excellent potential in bulletproof body armor application for minimizing the effect of blunt force trauma with less expensive materials usage and light weight ballistic panel.

View
Thumbnail Image
Publication

Aerodynamic and aeroacoustic performance of high-lift airfoil fitted with slat cove fillers

2020-08-04 , Kamliya Jawahar H. , Syamir Alihan Showkat Ali , Azarpeyvand M. , Ilário da Silva C.R.

Experimental measurements were carried out to assess the aerodynamic and aeroacoustic performance of an MDA 30P30N airfoil fitted with two different types of slat cove fillers. The aerodynamic results are presented for lift and drag measurements and mean surface pressure measurements, while the aeroacoustic results are presented for the near-field surface pressure fluctuations and far-field noise measurement. The flow measurement results show that there is no significant difference in the aerodynamic lift and drag between the tested cases, however, the slat cove filler configurations exhibit a much better lift-to-drag performance. The pressure coefficient results show that the use of slat cove fillers lead to a slight decrease in the suction peak over the main-element of the airfoil. In order to better understand the flow-field and the noise generation mechanism of the airfoil with slat cove fillers, simultaneous near-field and far-field noise measurements were carried out. The result shows that the use of the slat cove filler can generally lead to a significant reduction of the broadband noise and eliminate the characteristic tonal noise generated by the slat. The directivity pattern and the overall sound pressure level of the radiated noise have shown that a significant noise reduction can be achieved with the applications of the slat cove fillers. The multiple tonal phenomena generated by the slat were also analyzed using the continuous wavelet transform method and higher order spectral analysis methods.

View
Thumbnail Image
Publication

Experimental and finite element modeling of partial infill patterns for thermoplastic polymer extrusion 3D printed material using elasto-plastic method

2020-10-26 , Mohd Sabri Hussin , Sanusi Hamat , Syamir Alihan Showkat Ali , Muhammad Aiman Ahmad Fozi , Yuzairi Abdul Rahim , Mohd Syedi Imran Mohd Dawi , Darsin M.

Fused Deposition Modeling is known as one of the 3D printing technology where it used a thermoplastic filament to produce a prototype or a 3D part. FDM will print out the 3D part, layer by layer on the platform of the 3D printer from bottom to top using the extruded molten thermoplastic. However, there is no information about the volume enclosed by the boundary surface of the 3D part by commonly used model data format such as STL file, since the volume enclosed can be completely or partially filled. Therefore, the study and research have been carried out to investigate the strength of the 3D part affected by the design of the infill pattern where three methods being used which are design, experiment and simulation. The 3D parts were designed using CATIA V5 following the ASTM D638 for tensile test and ASTM D695 for compression test. The 3D design was then being printed using the Fused Deposition Modeling (FDM) technique for experimental purposes and to perform the quasi-static test. Furthermore, the 3D printed with infill pattern test data were then being imported to ABAQUS/Explicit software for non-linear finite element analysis using elasto-plastic approach. The best infill patterns that exhibit a better strength after the 100% fill part is the 30% fill Lines pattern. It can be concluded that the average percentage error of stress and strain values between experimental test and simulations in tensile and compression for all specimens is below than 10%.

View
Thumbnail Image
Publication

The Effects of Self-Polymerized Polydopamine Coating on Mechanical Properties of Polylactic Acid (PLA)–Kenaf Fiber (KF) in Fused Deposition Modeling (FDM)

2023-06-01 , Sanusi Hamat , Syamir Alihan Showkat Ali , Salit M.S. , Yidris N. , Showkat Ali S.A. , Mohd Sabri Hussin , Muhamad Saifuldin Abdul Manan , Muhamad Qauyum Zawawi Ahamad Suffin , Maliki Ibrahim , Ahmad Nabil Mohd Khalil

This research examines the impact of self-polymerized polydopamine (PDA) coating on the mechanical properties and microstructural behavior of polylactic acid (PLA)/kenaf fiber (KF) composites in fused deposition modeling (FDM). A biodegradable FDM model of natural fiber-reinforced composite (NFRC) filaments, coated with dopamine and reinforced with 5 to 20 wt.% bast kenaf fibers, was developed for 3D printing applications. Tensile, compression, and flexural test specimens were 3D printed, and the influence of kenaf fiber content on their mechanical properties was assessed. A comprehensive characterization of the blended pellets and printed composite materials was performed, encompassing chemical, physical, and microscopic analyses. The results demonstrate that the self-polymerized polydopamine coating acted as a coupling agent, enhancing the interfacial adhesion between kenaf fibers and the PLA matrix and leading to improved mechanical properties. An increase in density and porosity was observed in the FDM specimens of the PLA–PDA–KF composites, proportional to their kenaf fiber content. The enhanced bonding between kenaf fiber particles and the PLA matrix contributed to an increase of up to 13.4% for tensile and 15.3% for flexural in the Young’s modulus of PLA–PDA–KF composites and an increase of up to 30% in compressive stress. The incorporation of polydopamine as a coupling agent in the FDM filament composite led to an improvement in tensile, compressive, and flexural stresses and strain at break, surpassing that of pure PLA, while the reinforcement provided by kenaf fibers was enhanced more by delayed crack growth, resulting in a higher strain at break. The self-polymerized polydopamine coatings exhibit remarkable mechanical properties, suggesting their potential as a sustainable material for diverse applications in FDM.

View